Semiconductor structure and manufacturing method thereof

ABSTRACT

A semiconductor structure and a manufacturing method thereof are provided. The method includes the following steps. Firstly, a semiconductor substrate having an active surface and a back surface is provided. The active surface is opposite to the back surface, and the semiconductor substrate includes at least one grounding pad disposed on the active surface. Secondly, at least one through silicon via is formed through the semiconductor substrate from the back surface to the active surface thus exposing the grounding pad. Then, a conductive layer is formed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connect to the grounding pad and the semiconductor substrate.

RELATED APPLICATIONS

This application is a continuous application of U.S. patent application Ser. No. 12/775,114, filed on May 6, 2010, and the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a semiconductor structure and a manufacturing method thereof, and more particularly to a semiconductor structure with uniformly grounded electricity and a manufacturing method thereof.

2. Description of the Related Art

In traditional packaging technique of semiconductor, grounding pads disposed on a chip are electrically connected to external grounding device by wire bonding process. Further, each grounding pad has to connect with many wires for transmitting high power current in high power chip and high frequency chip.

However, since the amount of the wires which are allowed to connect to a single grounding pad is limited by the area of each grounding pad, the layout of the wires becomes more difficult as the size of recent semiconductor device is reduced. Additionally, because the distances between each grounding pad and the external grounding device are different, the lengths of the used wires are also different. If the length of the wires is over long, the electricity may be decayed and the electricity of the grounding pad and the external grounding device may not be matched to each other.

Therefore, how to reduce the transmittance distance of the grounding signal of the chip, is an important problem.

BRIEF SUMMARY

Accordingly, the present invention is directed to a manufacturing method of a semiconductor structure to improve the grounding signal transmission quality.

The present invention is also directed to a semiconductor structure with uniform grounded character and improved operating efficiency.

The present invention provides a manufacturing method of a semiconductor structure including the following steps. First, a semiconductor substrate having an active surface and a back surface and including at least one grounding pad disposed on the active surface is provided. Next, at least one through silicon via is formed through the semiconductor substrate from the back surface to the active surface and thus exposing the grounding pad. Then, a conductive layer is formed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connect to the grounding pad and the semiconductor substrate.

In one embodiment of present invention, before forming the through silicon via, the method for manufacturing semiconductor structure further includes the step of adhering the active surface of the semiconductor substrate to a carrier substrate. Furthermore, after forming the conductive layer, the semiconductor substrate is separated from the carrier substrate.

In one embodiment of present invention, the semiconductor substrate includes at least one power supply/signal pad disposed on the active surface. In addition, after separating the semiconductor substrate from the carrier substrate, a wire bonding is further performed on the active surface of the semiconductor substrate to electrically connect the power supply/signal pad and external circuits.

The present invention also provides a semiconductor structure including a semiconductor substrate and a conductive layer, wherein the semiconductor substrate has an active surface and a back surface. The active surface is opposite to the back surface, and the semiconductor substrate includes at least one grounding pad disposed on the active surface. In addition, there is at least one through silicon via through the semiconductor substrate from the back surface to the active surface and thus exposing the grounding pad. The conductive layer is disposed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connect to the grounding pad and the semiconductor substrate.

In one embodiment of present invention, the semiconductor substrate further includes at least one power supply/signal pad disposed on the active surface.

In one embodiment of present invention, the power supply/signal pad is disposed closer to the edge of the semiconductor substrate compared to the grounding pad.

In one embodiment of present invention, the conductive layer is made of, for example, copper or aluminum.

In the present invention, at least one through silicon via is formed on the semiconductor substrate and exposing the grounding pad. Then, a conductive layer is formed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connect to the grounding pad. In other words, the present invention uses TSV (Through-Silicon Via) technology to fabricate the transmission path of ground signal. Compared to the conventional wire bonding art, the present invention increases the transmission density of ground signal per unit area.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

FIGS. 1A to 1E are cross-sectional schematic views of a manufacturing process of a semiconductor structure according to an embodiment of the present invention.

FIG. 2 is a cross-sectional schematic view of a part of a manufacturing process of a semiconductor structure according to another embodiment of the present invention.

FIG. 3 is a cross-sectional schematic view of a part of a manufacturing process of a semiconductor structure according to another embodiment of the present invention.

DETAILED DESCRIPTION

FIGS. 1A to 1E are cross-sectional schematic views of a manufacturing process of a semiconductor structure according to an embodiment of the present invention. Referring to FIG. 1A, a semiconductor substrate 110 having an active surface 112 and a back surface 114 is provided, and the active surface 112 is opposite to the back surface 114. In this embodiment, the semiconductor substrate 110 is, for example, a wafer, but the present invention is not limited hereto. In other embodiment, the semiconductor substrate 110 may be chip died from a wafer. Furthermore, the semiconductor substrate 110 includes at least one grounding pad 116 disposed on the active surface 112. Specifically, a plurality of material layers 115 are formed on the active surface 112 of the semiconductor substrate 110, and the ground pad 116 may be disposed in any material layer. In order to describe conveniently, FIG. 1A only shows a single material layer 115 and plurality of ground pads 116 therein. In the embodiment, the semiconductor substrate 110 further includes at least one power supply/signal pad 118 disposed on the active surface 112 the same as the ground pads 116.

It is worth to say that since the power supply/signal pads 118 are electric connected to external circuit by wire bonding process, the power supply/signal pads 118 of this embodiment are disposed closer to the edges of the semiconductor substrate 110 comparing to the grounding pads 116. Thus, it is convenient to performing the wire bonding process of the power supply/signal pads 118.

Referring to FIG. 1B, the semiconductor substrate 110 is adhered to the carrier substrate 130 in the present embodiment to prevent the semiconductor substrate 110 from damaging caused by the insufficient rigidity in the subsequent process. For example, the semiconductor substrate can be adhered to the carrier substrate 130 through an adhering layer 135, and the active surface 112 is contacted with the adhering layer 135. Moreover the adhering layer 135 can be an adhering layer having a temporary adhesive effect, such as ultraviolet adhesive, hot melt adhesive or dissolvable adhesive that may be dissolved by a solvent, but the invention is not limited hereto. Further more, the carrier substrate 130 is, for example, a transparent plastic substrate.

It should be noted that, in the embodiment, the adhering layer 135 spreads between the carrier substrate 130 and the semiconductor substrate 110 completely. However, in other embodiments, the adhering layer 135 may be patterned to distribute between the carrier substrate 130 and the semiconductor substrate 110, as shown in FIG. 2. As such, the adhering layer 135 may not be in contact with the semiconductor elements (not shown) on the active surface 122 of the semiconductor substrate 110, and thus, the semiconductor elements can be prevented from damage caused by removing the adhering layer 135.

Referring to FIG. 1C, at least one through silicon via 120 is formed in the semiconductor substrate 110, so as to expose the grounding pad 116. Specifically, the amount of the through silicon vias 120 is equal to the amount of the grounding pads 116. Therefore, all grounding pads 116 disposed on the active surface 112 can be exposed by the through silicon vias 120. The through silicon vias 120 can be formed from the back surface 114 through to the active surface 112 by laser drilling or deep reactive ion etching (DRIE), but the invention is not limited hereto.

Referring to FIG. 1D, a conductive layer 140 is formed on the back surface 114 of the semiconductor substrate 110 and filled into the through silicon vias 120 to electrically connect to the grounding pads 116. During the follow-up process, the grounding pads 116 are electrically connected to the external grounding device (not shown) through the conductive layer 140. It should be noted that the conductive layer 140 is immediately filled into the through silicon vias 120 and there is not any insulating material formed between the conductive layer 140 and the semiconductor substrate 110. That is, all grounding pads 116 disposed on the active surface 112 can electrically connect to each other through the conductive layer 140 and the semiconductor substrate 110, so the grounding pads 116 has uniform grounding electricity. Therefore, the aforementioned process is suitable to be used for manufacturing semiconductor device with high frequency or high power.

In this embodiment, the material of the conductive layer 140 may be copper or aluminum, but the invention is not limited hereto. Moreover, although the conductive layer 140 of this embodiment is conformally filled into the through silicon vias 120, the conductive layer 140 also may be filled the through silicon vias 120 to the full in other embodiments, as shown in FIG. 3, but the invention is not limited hereto.

Referring to FIG. 1E, the carrier substrate 130 is separated from the semiconductor substrate 110 after forming the conductive layer 140. A semiconductor structure 100 is substantially made. The method for separating the semiconductor substrate 110 from the carrier substrate 110 is according to the material of the adhering layer 135. For example, the method can be irradiating the adhering layer 135 by ultraviolet light, hot melting the adhering layer 135, mechanical stripping the adhering layer 135 or dissolving the adhering layer 135 by a solvent. After that, the semiconductor structure 100 also can be cut or packaged by well-known process.

Furthermore, if the semiconductor substrate 110 is a chip died from wafer, a wire bonding process is performed on the active surface 112 to electrically connect the power supply/signal pads 118 to external circuit (not shown) after separating the semiconductor substrate 110 from the carrier substrate 130.

In summary, in the present invention, at least one through silicon via is formed on the semiconductor substrate and exposing the grounding pad. Then, a conductive layer is formed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connect to the grounding pad. In other words, the present invention uses TSV (Through-Silicon Via) technology to fabricate the transmission path of ground signal. Compared to the conventional wire bonding art, the present invention increases the transmission density of ground signal per unit area.

Moreover, since there is not any insulating material formed between the conductive layer and the semiconductor substrate, the grounding pads disposed on the semiconductor substrate can uniformly transmit grounding signals to external grounding device through the conductive layer. Therefore, the operation efficiency of the semiconductor structure of the invention may be improved.

The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including configurations ways of the recessed portions and materials and/or designs of the attaching structures. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments. 

What is claimed is:
 1. A method for manufacturing semiconductor structure, comprising steps of: providing a semiconductor substrate having an active surface and a back surface on opposite sides thereof, wherein the semiconductor substrate comprising at least one grounding pad disposed on the active surface; forming at least one through silicon via through the semiconductor substrate from the back surface and thus exposing the grounding pad; and forming a conductive layer on the back surface of the semiconductor substrate, and the conductive layer filled into the through silicon via to electrically connected to the grounding pad and the semiconductor substrate.
 2. The method claimed in claim 1, further comprises a step of adhering the active surface of the semiconductor substrate to a carrier substrate before forming the through silicon via.
 3. The method claimed in claim 2, further comprises a step of separating the semiconductor substrate from the carrier substrate after forming the conductive layer.
 4. The method claimed in claim 3, wherein the semiconductor substrate further comprises at least one power supply/signal pad disposed on the active surface, and the method further comprises the step of performing a wire bonding for the power supply/signal pad after separating the semiconductor substrate from the carrier substrate.
 5. A semiconductor structure, comprising: a semiconductor substrate having a active surface, a back surface and at least one through silicon via and comprising at least one grounding pad disposed on the active surface, wherein the active surface is opposite to the back surface, the through silicon via is formed through the semiconductor substrate from the back surface to the active surface and thus exposing the grounding pad; and a conductive layer disposed on the back surface of the semiconductor substrate and filled into the through silicon via to electrically connected to the grounding pad and the semiconductor substrate.
 6. The semiconductor structure claimed in claim 5, Wherein the semiconductor substrate further comprises at least one power supply/signal pad disposed on the active surface.
 7. The semiconductor structure claimed in claim 6, wherein the power supply/signal pad is disposed closer to the edge of the semiconductor substrate comparing to the grounding pad.
 8. The semiconductor structure claimed in claim 5, wherein materials of the conductive layer comprises copper or aluminum. 